TM1 Forum

Hello everyone,

Do you have any advice on when to use several TM1 instance (model, server whatever you call it) instead of just using one massive one? I'm currently rebuilding my new employers TM1-monster and adding a lot of much needed functionality to it. This of course makes a fairly large model grow even bigger.

I feel like Im trying to find reasons why I must split it into several smaller parts because I want to be able to reboot everything fairly quickly, should something go wrong. It also helps if I need to change parts of the model. I do however feel like its quite ok with one massive model and the thought of having to maintain the same dimensions in several places just feels wrong. And since the data amounts would require me to export and import files between the models, that doesn't exactly make me love the idea.

But Im lacking experience and Im sure some of you out there know of several pitfalls down the line if I dont split this up into smaller models.

The amount of TM1 instances you have depends heavily on your business requirements, not just technical issues.

There are technical issues that you have to take into account, such as the size of the model. If the model takes too long to load, or if a dimension cannot open because it is too large, the model is rendered unusable and that would cause you to think about splitting it up.

But business requirements will be the main thrust of your decision making. Perhaps you have yearly snapshots of your actuals. This would be a good time to think about a new TM1 instance, a server dedicated to historical data, locked down dimensionally.

There may be separate parts of your system, such as planning and payroll. It would be better if your payroll model stood alone and your planning data to be part of an IBP.

You can also have separate models for administration and audit information. A separate model dealing with just the administration of your server can allow you to work with just the necessary data needed for a TM1 administrator, who may not need access to the planning part of your system.

In short, it depends on how your business operates as well as the technical and performance issues.

Trevor.

Yes, I think I will try to break it up based on what I would put in different TM1-applications. But I will wait untill Im done with everything and see if the performance is good enough to keep it running as one large model.

I would avoid breaking it up unless it's necessary for performance reasons. Once you have two models, assuming there is some information which needs to be stored in both, you introduce the need to synchronize them. Whether that's via replication or your own export/import processes, you're adding a lot of complexity and potential for errors. If you allow writing to the same cells on both systems, recovering from a synchronization error can be particularly time consuming-- and unless you have a solid monitoring system in place errors can creep in for some time before you notice that you have a problem.

I speak from experience. We've since sold several foreign subsidiaries, but at the peak I was keeping eight geographically-separated TM1 models synchronized. I pulled more than one all-nighter recovering from de-sync events back when replication was flakier.

Matt